DOHA (AFP) - Five leading Afghan militants freed from Guantanamo Bay in exchange for a US soldier have pledged to honour an agreement between the Taleban and Qatar, which is hosting them.

The men, officials in the Taleban regime driven from power by the US-led invasion of Afghanistan in 2001, were released on May 31 and flown to Qatar in exchange for US army sergeant Bowe Bergdahl.

Their release provoked criticism from some US politicians, who said they could pose a threat to Americans abroad, and anger from Afghans opposed to the Taleban.

But in a statement posted on their Pashto-language website on Friday, the men said they would remain faithful to an agreement with Qatar, which mediated their release.

"We want to reassure all sides that we are still holding to the agreement which was reached between the Islamic Emirate (the Taleban) and the government of Qatar on our release," they said, urging the release of fellow Taleban militants held in Guantanamo.

The freed prisoners are Mohammad Fazl, Norullah Noori, Mohammed Nabi, Khairullah Khairkhwa and Abdul Haq Wasiq.

Little has been revealed about the deal, but Qatar has said it will impose a one-year travel ban on the men.

US President Barack Obama is facing intense scrutiny over the deal to secure Bergdahl's release after five years.

He said Qatar had set up a process to monitor the prisoners and the US would also be "keeping eyes on them".

But Obama admitted it was possible some of them could return to activity "detrimental" to the United States.